An electronic apparatus may be disconnected from an AC power source ("OFF" mode), connected to the AC power source ("STANDBY" mode) or energized for use ("ON" mode). Safety regulations in some countries require consumer electronic product such as television receivers to have at the front panel an indicator light which is illuminated as soon as the television receiver is plugged into an AC power outlet. This indicator light should be bright enough to be seen in a well-lighted room and visible from different angles to warn the owner that the television receiver is plugged in. The indicator is provided so that if, e.g., the owner leaves home for a protracted period of time, there is a reminder to unplug the receiver.
Various indicator systems are known. For example, in television receivers manufactured for the domestic Japanese market it is known to use a combination of red and green light emitting diode (LED) indicators to visually indicate the three modes as follows: if both LEDs are off (dark), then the receiver is in the OFF mode (unplugged); if the red LED is on and the green LED is off, then the receiver is in the STANDBY mode; and if the red LED is off and the green LED is on, then the receiver is in the ON mode. Other known techniques include illuminating a single red LED to indicate both the STANDBY and ON modes, illuminating a single red LED only in STANDBY mode, and using one segment of a seven segment LED to indicate STANDBY mode where the seven segment display normally indicates a tuned channel number in the ON mode.
One of the deficiencies in the above indicator systems is the fact that two LEDs may be necessary, thereby increasing the cost of the indicator system. Another deficiency is the distracting affect of an indicator to a viewer of a television system. Since the STANDBY and ON mode indicators must be visible in a well lit room, one or more of the indicators may have a distracting affect when a viewer is watching television in a dimly lit room. It is therefore desirable to implement a mode indicating system using only one indicating light source (e.g., an LED). It is also desirable to reduce the distracting influence of the mode indicator on the user of apparatus equipped with the indicator system.